Bird-Scaring Lines
WHAT ARE BIRD SCARING LINES?
Bird-scaring lines (also known as streamer lines or tori lines) are an effective method for significantly reducing seabird bycatch in longline and trawl fisheries. Simple and economical, bird-scaring lines are towed from the stern of the vessel, over the area where the baited hooks are deployed.
Brightly coloured streamers attached to the backbone of the line act as a ‘scare-crow’, keeping birds from getting tangled in the baited hooks. A towed object is attached at the end of the line to create additional drag and stabilise the line in high winds. Bird-scaring lines should be deployed before the fishing gear is shot-away, and reeled back once the final hook has been set.
Using two lines together is considered best practice (see image). Additionally, it has been suggested that bird-scaring lines are to be used in combination with weighted branchlines (ensuring hooks sink rapidly) and night setting (avoiding peak seabird activity) to maximise bycatch reduction.
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Source: ACAP
CURRENT RESEARCH & USE
Bird-scaring lines are considered best practice and an effective measure by the Agreement for Conservation of Albatrosses and Petrels (ACAP) to reduce incidental bycatch of seabirds in demersal and pelagic longline fisheries.
In 2004/2005, the South African hake trawl fishery was found to result in a significant number of albatross deaths by cable strikes, mostly during the discarding of offal (fish waste). Bird-scaring lines were introduced as a mitigation method, and by 2010, seabird mortality fell by 73-95% compared with 2004.
Bird-scaring lines have been tried and tested in various fisheries around the world. A 2021 study reported a 98.4% reduction in seabird bycatch in Namibian demersal longline hake fisheries.
Bird-scaring lines are required by law in Namibian and Australian longline fisheries, Argentinian trawl fisheries, Brazilian pelagic longline fisheries, Chilean longline and trawl fisheries, and South African hake trawl, demersal and pelagic longline fisheries. Bird-scaring lines are not yet a legal obligation in UK fisheries, but are growing in popularity due to their simplicity and efficacy.
More recently, a device has been tested in Portuguese artisanal purse seine fisheries called ‘SCARYBIRD’, which has a harrier shape to scare away prey birds and can be affixed either to the fishing vessel or to buoys. Although no mortality related to bycatch events happened during the trial, the device reduced the presence of gulls by 11%. The results are thus promising, but tests in other fisheries are needed.
Source: ACAP
This page was last updated on 20.12.22.
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